Thanks, Nigel

Every single time, burrowing into it has resulted in two things - less knowledge and more damage than was expected.

Aye, but if we were those to leave well enough alone ...

It's evident we still have no real understanding of what goes on in there, particularly the hydrological processes.

Due to the unmanageable, unknowable, variables involved in of a mound built of chalk fragments & blocks, (with a core of various other materials); a true calculation seems impossible, now & forever. However, by testing the permeability of the cores, (where these have cut virgin material), a reasonable average might be arrived at. Set in a spring-filled moat, the Hill will have humidity rising from below, (through the chalk) as well as rain percolating down. In aggregate, it might therefore be comparable to, but a bit more variable than, (due to the elevation and fissuring), chalk bedrock set above the mean water-table

It was able to preserve the original vegetation, (Merewether & Atkinson found), and this argues that water did not move rapidly through it -- otherwise dissolved oxygen should have fueled microbial growth which would have attacked this

If the question is restoring the old hydrology, quarried chalk seems the best answer. It could, I imagine, be baked for sterilization, then colored, (waterfast), to identify it to future expeditions as new material. It's somewhat amusing to think of the greatest man-made mound in Europe being repaired with ... colored chalk. Contractor Blue

Once the reports come out, there may be another look at Silbaby